Applicants hereby claim priority based on Swiss Patent Application No. 837/99 filed May 5, 1999.
The present invention relates to a conveying apparatus having a modular conveying belt and at least one toothed drive wheel.
Known modular conveying belts are made up of a plurality of modules in which each has a plate-like module body and a first and second series of articulation-eyelet elements which project from two opposite sides of the module body. Each of these articulation-eyelet elements comprises an articulation eyelet, it being the case that the articulation eyelets of each of the two articulation-eyelet-element series are aligned in order to receive a continuous articulation rod. Two adjacent modules interengage and are articulated on one another by an articulation rod which passes through the articulation eyelets of one articulation-eyelet-element series of one module and the articulation eyelets of one articulation-eyelet-element series of the other module. The modules are usually offset with respect to one another, with the result that it is possible to form a conveying belt of the desired length and width. The conveyable articles are transported on conveying surfaces of the module bodies and of the articulation-eyelet elements.
In certain applications, particularly in the foodstuffs industry, it is necessary to have a conveying-belt structure which can easily be cleaned. A modular conveying belt of this type is described, for example, in U.S. Pat. No. 4,925,016. In order to drive the conveying belt, a transverse rib is arranged on the underside of the module bodies, transversely to the conveying direction in each case. Longitudinal ribs have been dispensed with in order to ensure good cleaning. The conveying belt is driven by a plurality of parallel, spaced-apart toothed drive wheels which have drive teeth which are positioned against the transverse ribs. Provided on the toothed drive wheels in addition to said drive teeth are guide teeth which each engage in the gap between two adjacent articulation-eyelet elements of interengaging modules and thus guide the modular conveying belt laterally.
This conveying apparatus known from U.S. Pat. No. 4,925,016 has the disadvantage that the toothed drive wheels have guide teeth in addition to the drive teeth, that is to say they involve relatively high outlay in structural terms. Moreover, the additional guide teeth make cleaning more difficult and there is a risk of conveyable articles passing onto the conveying-belt underside being pressed by said guide teeth into the narrow interspace between two adjacent articulation-eyelet elements, from where they were very difficult to remove again.
In view of the disadvantages of the hitherto-known, above-described, modular conveying belts and toothed drive wheels, the object of the invention is to provide a conveying apparatus of the type mentioned in the introduction in the case of which the toothed drive wheel or the toothed drive wheels, which serves/serve both for driving and for guiding the modular conveying belt, is/are of as straightforward a construction as possible. The conveying belt and the toothed drive wheel or wheels are also intended to be easy to clean.
The object is achieved by the conveying apparatus according to the invention as is defined in independent Patent Claim 1. Preferred design variants can be gathered from the dependent patent claims. Independent Patent Claims 9 and 10 related respectively to a toothed drive wheel and to a modular conveying belt according to the invention.
The invention relates to a conveying apparatus having a modular conveying belt which is made up of a plurality of modules, and having at least one toothed drive wheel. The modules each have a plate-like module body and a first and second series of articulation-eyelet elements which project from two opposite sides of the module body and each comprise an articulation eyelet. Two adjacent modules interengage and are articulated on one another by an articulation rod which passes through the articulation eyelets of one articulation-eyelet-element series of one module and the articulation eyelets of one articulation-eyelet-element series of the other module. The at least one toothed drive wheel has teeth for driving the conveying belt. The essence of the invention, then, resides in the fact that the modules and the at least one toothed drive wheel are designed and arranged such that, during driving of the conveying belt, the teeth each engage between two adjacent articulation-eyelet elements of a module, in order to form direct lateral guides for these two articulation-eyelet elements.
By virtue of the invention, the toothed drive wheels can be produced in a more straightforward manner than in the case of the hitherto-known conveying apparatuses having modular conveying belts which have modules with plate-like module bodies. Instead of separate drive and guide teeth, both the drive function and the guidance function are performed by the same teeth. Since these teeth do not engage in the gap between two adjacent articulation-eyelet elements of interengaging modules, the risk of conveyable articles passing onto the conveying-belt underside being pressed into the gap is reduced to a considerable extent.
Moreover, it is possible to use the same toothed drive wheels both for modular conveying belts with continuous conveying surfaces and with conveying surfaces which are provided with openings, e.g., grid-like conveying surfaces, as well as for conveying belts which do not have any gaps between two adjacent eyelets. A single toothed-drive-wheel shape is sufficient for all belt types with the same pitch. A cost-effective solution with straightforward storage is thus provided.
Since, alongside the articulation-eyelet elements and the transverse ribs which are provided in a fair number of design variants, there are no additional elements for belt guidance, e.g., ribs or protuberances, on the underside of the modular conveying belt, the latter is also easy to clean.